Method and System for Filling and Venting a Device for Extracorporeal Blood Treatment, with Stepped Flooding of a Filter

ABSTRACT

A method for filling and venting a device for extracorporeal blood treatment is disclosed, such as a patient module in a heart-lung machine, without attached patient. A filling liquid from a filling liquid container located higher than the device flows by gravity via a venous side of the system into a reservoir and flows onwards into a blood pump located at the lower end of the reservoir, wherein a first controllable valve (HC 1 ) for a venting line of a filter is opened and, after the response of an upper filling level sensor in the reservoir, is closed. An upper level of the filter is positioned higher than the upper filling level sensor, and a start-stop motion of the blood pump is performed, as a result of which a stepped flooding of the filter is made providing for an advantageous de-airing of the device.

FIELD OF THE INVENTION

The present invention relates generally to a method and devices forcarrying out extracorporeal blood treatment, and to a system and kitcomprising such devices. In particular, the present invention relates tosystems, such as heart-lung machines, and associated devices forextracorporeal blood treatment, such as patient modules, and associatedventing methods.

BACKGROUND OF THE INVENTION

Before a heart-lung machine can be used, it has to be prepared such thatthe patient can be connected quickly and safely to the system. Thisrequires a machine in which the blood-conveying components are vented(also called “de-aired”) by a filling liquid. The filling procedure isalso called “priming” of the machine.

Air inclusions or released quantities of air can, during later use onthe patient, cause air embolisms and, in the worst case, death.

Components and hose systems in conventional heart-lung machines arehitherto for the most part prepared for use by being filled and ventedmanually. The preparation is performed, for example, by partial fillingof components, manual clamping of hose lines, “beating out” of airbubbles, tilting of components, or cyclical driving of the blood pumps.Components such as hoses, connectors and reservoir have to be vented inaddition to components such as oxygenator, filter and blood pumps. Whenventing a conventional heart-lung machine by filling it, the fillingprocedure has to be carried out by experts (cardio technicians). Thisapplies also to regular operation. By means of the manual interventionsdescribed above, the system is made ready for use. In some systems, thefilling procedure takes place semi-automatically but neverthelessrequires trained personnel and/or cardio technicians, who perform thefilling procedure. In the semi-automatic method, the operator partly hasto clamp hoses, initiate pump actions, etc.

Generally, these manual interventions are complicated and cost-intensivein terms of personnel. These manual interventions are also susceptibleto error and are difficult to document.

The use of the manual interventions, particularly in emergencysituations, causes difficulties for the patient, who is reliant on arapid start-up of the heart-lung machine. In addition, the costs and thetime that are needed for the intervention increase.

The European patent specification EP 1,661,592 B1 by LifebridgeMedizintechnik AG describes a portable heart-lung machine withsemi-automatic filling. These portable heart-lung machines consist of abase station and of a control module with attached patient module. EP1,661,592 is herewith incorporated by reference in its entirety and forall purposes. The patient module contains the blood conveying componentsand is disposed of after use by separation from the control module. Thebloodconveying components include the blood pump, in the form of acentrifugal pump, a reservoir with filling level sensors, an arterialfilter, an oxygenator, various connecting hoses and bypasses, and alsosensors for detecting air and gas bubbles and for measuring pressure andflow.

In the portable heart-lung machine that is described in EP 1,661,592 B1,the components are filled and vented by manual rotation of the completeunit through 90° to a filling position. In the filling position, anautomatic method is then initiated that permits filling. After thefilling procedure, the unit is rotated back through 90° to a filledoperating position. By the rotation to the operating position and by amethod for automatic detection and elimination of air bubbles, thesystem is brought to the operating state.

However, for the rotation movement during venting, an additionalmechanical rotary holder is needed in order to move the control modulewith the patient module from the operating position to the fillingposition and back again.

Moreover, in the manual and also in the semi-automatic systems, there isthe danger of air inclusions being overlooked or undetected despitevisual inspection of the components.

US Patent application number US2008/171960 of the same applicant as thepresent applicant, which hereby is incorporated by reference in itsentirety for all purposes, an apparatus is disclosed for makingextracorporeal blood circulation available, in a particular a heart-lungmachine, comprising a venous connection and an arterial connection,between which a blood reservoir, a blood pump and a bubble detector forthe detection of air bubbles are provided, with, downstream of thebubble detector, an arterial line leading to the arterial connection viaan arterial clamp and a bypass leading via a bypass clamp back into theblood reservoir which is connected to a pump extracting air from theblood reservoir. In addition, a method is disclosed of operating such anapparatus. In WO 2005/065743 an EXTRACORPOREAL BLOOD CIRCUIT PRIMINGSYSTEM AND METHOD are disclosed. A disposable, integrated extracorporealblood circuit is disclosed that is employed during cardiopulmonarybypass surgery performs gas exchange, heat transfer, and microembolifiltering functions. A manual priming method is described.

Hence, there is a need to provide for improved priming methods andsystems allowing for such improved priming. Advantageously, the primingshould be done automatically.

Therefore, an aim of the disclosure is to ensure that a heart-lungmachine can be vented fully automatically by filling, without input bythe operator, and thus made ready safely for use. No manualinterventions for venting should be performed on the components in thepatient module between starting up the machine (initialization, manualattachment of various hose lines and manual attachment of the fillingliquid) and the attachment to the patient. Moreover, the time needed forthe venting method is intended to be further reduced by eliminating thepreviously required rotation of the base module for the ventingprocedure. Thus, the system is made rapidly available for use,especially for short-term emergency use.

It is therefore desirable to make available a method for preparing andventing a heart-lung machine in the form of a portable heart-lungmachine, which method can take place without intervention of theoperator. It is desirable in particular that, after the attachment ofthe filling liquid and the attachment of the table line, the fillingprocedure should be started manually and proceed fully automatically.

Components that are difficult to vent, such as a blood pump and anarterial filter, are preferably to be made available in such a way that,in the venting method, the air in the components can advantageously bepurged and escape. Documentation of the venting procedure should be madepossible by the components and method.

SUMMARY OF THE INVENTION

An object of the disclosure is to overcome the abovementioneddisadvantages of the conventional methods and devices and to provide anadvantageous solution.

The abovementioned object is achieved by the device, systems, methods orcomputer programs of the invention having the characterizing features ofthe attached independent claims.

Reliable filling, even during transport, increases the range of possibleapplications of the system and methods described hereinafter.

Accordingly, embodiments of the present invention preferably seek tomitigate, alleviate or eliminate one or more deficiencies, disadvantagesor issues in the art, such as the above-identified, singly or in anycombination by providing the described methods and devices have at leastthe advantages set forth below.

A method is provided for preparing and venting in a device forextracorporeal blood treatment, such as a heart-lung machine, preferablyin the form of a portable heart-lung machine, can proceed withoutintervention of the operator. Only the preparation and initiation of theprocedure are necessary. The remainder of the procedure takes placeautomatically and is monitored. After the attachment of the fillingliquid and the attachment of the table line, the filling procedure isstarted manually and then takes place fully automatically.

The system for extracorporeal blood treatment, such as preferably aheart-lung machine, can be filled not only in a stationary environmentbut also during transport.

Air can be purged and escape from components of the device forextracorporeal blood treatment that are difficult to vent, such as theblood pump and the arterial filter, by virtue of the design andarrangement of the components and the venting method.

It is possible to monitor and record the venting procedure in anelectronic protocol. The most important states of the system can bestored there. These include, for example, the state of clamps, times,sensors for parameters such as pressure, flow, air bubble detection.

It should be emphasized that the term “comprises/comprising” when usedin this specification is taken to specify the presence of statedfeatures, integers, steps or components but does not preclude thepresence or addition of one or more other features, integers, steps,components or groups thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects, features and advantages of which embodiments ofthe invention are capable of will be apparent and elucidated from thefollowing description of embodiments of the present invention, referencebeing made to the accompanying drawings, in which

FIG. 1 shows across-sectional view of an arterial filter in a normalfilling direction;

FIG. 2 shows across-sectional view of an arterial filter in a retrogradefilling direction;

FIGS. 3 and 4 show schematic views of a blood pump;

FIG. 5 shows a schematic overview of a circulation system for method 1;

FIG. 6 shows a schematic overview of a circulation system for method 2with retrograde filling;

FIG. 7 shows a schematic overview of a circulation system for method 1with integrated pressure measurement;

FIG. 8 shows a schematic overview of a circulation system for method 2with integrated pressure measurement;

FIGS. 9 a and 9 b show schematic diagrams of the steps of variousmethods; and

FIGS. 10 a and 10 b show a schematic diagram of various computerprograms for carrying out methods.

DETAILED DESCRIPTION OF THE INVENTION

While the invention will be described in different embodiments and withthe description of different methods for carrying out the invention, aperson skilled in the art will appreciate that these embodiments areonly illustrative, non-limiting examples of numerous forms that thepresent invention can take. The device for extracorporeal bloodtreatment is preferably arranged in a heart-lung machine. Otherapplications may for instance be in dialysis machines or the like inother embodiments.

More precisely, the described embodiments of the devices and of thesystem of the present invention are suitable for carrying out anautomatic venting method.

Several examples of such methods for carrying out venting in associationwith the filling of a heart-lung machine are described below in detail.

As has been mentioned above, in the portable heart-lung machinedescribed in EP 1,661,592 81, the components are filled and vented bymanual rotation of the complete unit through 90° to a filling position.After the filling procedure, the unit is rotated back through 90° to afilled operating position.

The filling step serves to vent the components located in the patientmodule and is carried out by a 90° rotation movement of the controlmodule with the patient module on the base station. When the controlmodule with the patient module is located in the filling position, theblood pump pumps the filling liquid from an attached infusion bag intothe system via the reservoir in a time-controlled manner. In this way,the components are filled with the filling liquid, and the air locatedtherein is led out. For the subsequent use, the control module with thepatient module is rotated back to the operating position, and theventing of the components is continued in the operating position for adefined time by further pumping of the filling liquid.

The rotation to the filling position, and therefore the venting of thesystem in this position, is required by two components, namely the pumphead of the blood pump (centrifugal pump) and the arterial filter.

The pump head is arranged in the system in the operating position insuch a way that the outlet of the pump points downwards and, therefore,any air possibly entering during operation rises inside the head,collects there and cannot pass into the circulation system. Were fillingto take place in the operating position, the air in the upper area ofthe pump head would not be able to escape. For this reason, the systemis rotated through 90° to the filling position, in order to allow theair to escape via the inlet of the pump head and therefore to ensureair-free filling.

The arterial filter is arranged in the system in the operating positionin such a way that, because of its structure, the outlet pointsdownwards and the inlet is arranged laterally at the top of the filter.If the filter is filled in the operating position from the inlet side(unfiltered side), the filling liquid crosses from the unfiltered sideto the filtered side and the filter fills up. On the filtered side, inthe inner filter area, the filling can lead to air inclusions in theupper area and also in the lower area. Air inclusions at the loweroutlet area of the filter can break away during operation and thus passinto the circulation. By contrast, if the filter is first filled fromthe venting line (purge line) arranged at the top of the filter and thenfrom the inlet side in the filling position (horizontal), the air in thefilter can be displaced. The rest of the air remaining in the filter isremoved from the filter via the venting line after the rotation to theoperating position (see FIG. 1).

Without a rotation of the system through 90°, difficulties couldhitherto arise in the venting of the blood pump and of the arterialfilter. It was hitherto possible for air bubbles to accumulate in one ormore of the components.

As regards the filter, it was also hitherto possible, during filling ofthe filter, for the membrane structure of the filter to be “closed” bythe surface tension of the filling liquid, thereby making ventingimpossible. The air could not escape through the wetted membrane.

Moreover, the rising air from the hose mounted at the output of thefilter collected in the outlet area of the filter. The air inclusion wasnot able to rise through the liquid flowing in from the input side andwas continuously “entrained” in the direction of the filter outlet andbroken up.

In principle, air bubbles could still be forced through a wettedmembrane at pressures higher than the capillary forces. In practice,however, this is not feasible for several reasons. The reservoir mightbe destroyed, for example. The filter might also be affected. The pumpmight become overloaded and fail. In addition, a pressure higher thanthe maximum operating pressure of the system would be needed, whichcould lead to leakages. Alternatively, components could be used thatpermit higher operating pressures. However, these are much moreexpensive and therefore not an alternative on the market.

In some embodiments of the invention, the pressure is briefly increasedat the end of the filling procedure, by means of the blood pump beingoperated at an increased pump speed. The pressure in the system ischosen such that it is below but close to the maximum operatingpressure.

The abovementioned disadvantages of the prior art are avoided byembodiments of the invention. Fully automatic filling with venting isthus made possible without rotation of the system through 90°. This isexplained in detail below.

The extracorporeal blood treatment system described in embodimentsconsists of a control module with attached patient module. The automatichose clamps, the blood pump drive and the evaluation and controlelectronics are located in the control module. The patient module is adevice for extracorporeal blood treatment. The components conveying thecirculating blood are located in the patient module. The system is thusconstructed in two parts. The operating position of the patient moduleis also its filling position. A rotary holder is dispensed with.

The components of the patient module that are shown in FIGS. 5 to 8 are,despite the schematic depiction, in their actual horizontal positionrelative to one another. This applies in particular to the reservoir 2,the blood pump 6, the oxygenator 3 and the filter 5. The particulars andsignificance of the positions of the components relative to one anotherare now explained in more detail by way of a number of embodiments.

Flow directions are illustrated in the diagrams by bold arrows on thecorresponding lines, hoses or components.

FIG. 5 shows a circulation system. The circulation is constructed asfollows: starting from the venous side, the venous line 15 ends in areservoir 2 with screen 28. Connected to the venous line 15 is a volumedose line 17 through which filling liquid from a storage container 45and, optionally, a liquid supplied during use can be introduced into thecirculation. This volume dose line 17 to the venous line 15 iscontrolled via a third hose clamp 23 (HC3).

The hose clamps described herein are general controllable valves forfluid lines. Fluid is understood as a liquid, such as blood or bloodsubstitute, or a gas, such as air.

The reservoir 2 has an input 12 from the venous line 15 and a rollerpump 39 with hose clamp function attached to the upper part 13 of thereservoir for the purpose of venting the reservoir 2, as described inthe European patent specification EP 1,705,375 81, which is incorporatedherein by reference in its entirety and for all purposes.

The reservoir 2 is equipped with an upper filling level sensor 10 and alower filling level sensor 11. The reservoir comprises a screen 28,which separates the inlet area and outlet area across ⅘ of the surfaceof the reservoir.

The reservoir 2 also has, in the lower area, an output to a blood pump6.

The blood pump 6 is preferably a centrifugal pump, as shown in FIGS. 3and 4. The outlet 62 of the blood pump 6 is directed tangentiallyupwards. The inlet 61 of the blood pump 6 is arranged axially. In orderto achieve the venting effect, the pump head can be rotated from theperpendicular position about 10° clockwise and about 20°counterclockwise as illustrated in FIG. 4.

The blood pump 6 downstream of the reservoir 2 has the axial inlet 61attached to the reservoir 2, and the tangential outlet 62 is connectedto the venous side of an oxygenator 3.

From an arterial attachment of the oxygenator 3, a liquid line, forexample a hose, runs to an arterial filter 5. The oxygenator 3 also hasattachments for an oxygen supply (not shown), and attachments for ahyperthermia device for controlling the temperature of the liquid in thecirculation system (not shown). The oxygenator 3 also has an attachmentfor a venting line 18, which is connected separably to the upper part ofthe reservoir via a second hose clamp 22 (HC2).

FIGS. 1 and 2 show an arterial filter 5 in different states. In additionto an outlet 51 to the arterial side, the arterial filter 5 also has aventing line 55 mounted on the upper part of the filter and leading tothe upper part 13 of the reservoir, which venting line 55 can be clampedshut by a first hose clamp 21 (HC1). The filter has an unfiltered side53 and a filtered side 54.

Arranged downstream of the arterial filter, there is an air bubblesensor 30 which, upon detection of air bubbles, activates a downstreamquick-action hose clamp 20 (QAHC). Such a QAHC 20 is described in theEuropean patent specification EP 1,698,371 B1, which is herewithincorporated by reference in full and for all purposes.

When an air bubble is detected by the bubble sensor, the QAHC 20 closesthe arterial line 42 and opens a fourth hose clamp 24 (HC4) for a bypass40, such that the liquid is pumped round the circuit until the detectedair bubble is no longer located in the circulation of the patient module1. Pressure and 20 flow sensors 34, 37, 38 are likewise integrated inthe circulation. Before the system is vented, a table set 33 is attachedto the venous attachment 32 b and to the arterial attachment 32 a, whichtable set 33 closes the circulation and is filled too during theventing. A patient is not attached to the circulation during the fillingprocedure.

The components in the patient module 1 are arranged in their positionsas follows.

The reservoir 2 is installed in a 45° inclined position. However, it canalso stand vertically in the system. The maximum filling level 100 ofthe reservoir 2 is regulated via the upper filling level sensor 10.During the filling procedure, the liquid level in the patient module 1can thus be regulated such that it is located below the top face 56 ofthe arterial filter 5. This arrangement avoids a situation where thefilter 5 is filled completely with liquid and the upper part of themembrane of the filter element 52 of the filter is thus wetted withfilling liquid. Air inclusions can pass through the still “open”,unwetted and therefore gaspermeable upper areas of the membrane of thefilter 5 and escape.

The top face of the oxygenator 3 lies below or at the same height as thetop face of the filter 5. The blood pump 6 on the reservoir 2 is locatedbelow the maximum filling level of the reservoir, below the horizontalposition of the upper filling level sensor 10. The blood pump 6 can alsobe arranged below the lower edge of the reservoir 2. Theliquid-conveying parts of the pump 6 are thus always located below theupper filling level sensor 10. The filling liquid can therefore passmerely by gravity from the filling liquid container 45 and through thetangential outlet 62 of the pump 6 to the downstream components. Thereis no danger of an air inclusion in the pump 6.

The patient module 1 for a heart-lung machine is provided with a supportstructure, which ensures the spatial arrangement of the componentsrelative to one another. Thus, the patient module 1 contains a bloodcircuit with a blood pump 6, an oxygenator 3 with a top face, a filter 5with a top face, and a reservoir 2. In the operating position of thepatient module, the components are arranged in a horizontal positionrelative to one another in the support structure. The top face of theoxygenator 3 lies below or at the same height as the top face of thefilter 5. The liquid-conveying parts of the blood pump 6 are locatedbelow the horizontal position of an upper filling level sensor 10 of thereservoir 2 and are thus located below the maximum filling level of thereservoir 2. The top face of the filter is higher than the upper fillinglevel sensor of the reservoir. Thus, a partial filling of the filter 5can be controlled, which permits an advantageous venting of the bloodcircuit.

In one embodiment, the filter 5 of the patient module has a venting lineattached to the top face, wherein an attachment point for the ventingline is higher than the upper filling level sensor 10.

The first controllable valve 21 (HC1) is arranged in the venting line ofthe filter. A control unit 302 (FIG. 10 a and b) of the heart-lungmachine is configured such that, after the response of the upper fillinglevel sensor 10, the first controllable valve 21 (HC1) is at leastpartially closed. The lower edge of the reservoir 2 has a lower edge,and the blood pump 6 lies below the lower edge or below a horizontallevel of the lower edge of the reservoir (not shown). Alternatively, theblood pump 6 lies at the height of the lower third of the reservoir.

The patient module can have an additional fifth hose clamp 25 (HC5). TheHC5 25 is arranged in the venous line 15 between volume dose inlet andreservoir 2 and a feed point of the filling liquid, which is higher thanthe reservoir, the filter and the oxygenator (see the embodiment of thepatient module in FIG. (6).

The heart-lung machine has a control unit for the fully automaticfilling and venting of a patient module according to the invention. Thecontrol unit, for filling and venting the patient module, is configuredto close the first controllable valve 21 (HC1), which is opened afterthe start of the filling procedure for the venting line of the filter 5,and after the response of the upper filling level sensor 10 in thereservoir 2, in order to control the active filling of the filter 5. Thefilling liquid from the filling liquid container 45, located higher thanthe patient module and connected thereto, thus flows by gravity via thevenous side of the system into the reservoir 2 and onwards into theblood pump 6 located at the lower end of the reservoir 2 and thenonwards into the filter 5.

Thus, an air cushion is created in the filter by the closed firstcontrollable valve 21 (HC1) and the therefore closed venting line. Theair cushion damps the flow behaviour of the incoming filling liquid. Afirst speed of the blood pump is chosen by the control unit 302 suchthat as low filling of the filter 5 from the inlet side takes place, andthis filter is only partially filled, and an upper area of the filtermembrane 52 remains unwetted by the filling liquid and thus remainsair-permeable for the further filling and venting procedure.

Moreover, in embodiments such as in FIG. 6, the control unit isconfigured to close the fifth controllable valve 25 (HC5) when thefilling liquid in the reservoir is detected by the lower filling levelsensor 11. As a result of this, a venous connection between volume doseinlet and the reservoir 2 is separated by means of the fifthcontrollable valve 25 (HC5). The filling liquid will now flow onlythrough the venous line via the bypass 40 to the arterial filter 5.Thus, by means of the pressure applied, the filter 5 is filled in aretrograde manner from the outlet side by gravity.

The patient module can comprise an air bubble sensor 30. The air bubblesensor is arranged so as to detect air in the system. When an air bubbleis detected by the sensor, the control unit is configured to switch offthe table set by means of the quick-action hose clamp (QAHC) 20. Thefourth controllable valve 24 (HC4) is opened again and the air in thesystem is led off via the reservoir.

The patient module provided in the heart-lung machine, allows for thefilling and venting procedure to be carried out during transport of themachine. Transport is an operative condition of such a machine thatprovides for different challenges than stationary operation. Forinstance, space is limited, e.g. in an ambulance or a helicopter.Moreover, access to operating personel may be limited. This makes it soimportant that automatic priming is provided in the reliable mannerdescribed herein.

The control unit 302 is adapted to carry out the venting fullyautomatically and, after the start of the venting procedure, to carryout all the sequences automatically until the venting procedure has beencompleted.

After the start, the volume dose line is opened by the thirdcontrollable valve 23 (HC3), and, in doing so, the second controllablevalve HC2 22, the fourth controllable valve 24 HC4 and the quick-actionhose clamp QAHC 20 and also the roller pump 39 with hose clamp functionare opened.

In some embodiments, the heart-lung machine is adapted to record thefilling and venting procedure and thus document the latter in readableform. For example, data such as the indexing positions of thecontrollable valves, filling levels of the reservoir, switch-on andswitch-off times, the response of the air bubble sensor and otherparameters such as pressure and flow can be stored in a storage unit.The control unit 302 can administer these data to and from the storageunit.

A non-transitory computer-readable storage medium encoded withprogramming instructions, said storage medium being loaded into acomputerized control system of an apparatus, and said programminginstructions causing said computerized control unit to control primingof apparatus prior to connection to a patient are described now.

A computer program 301 for controlling the filling and venting of apatient module is shown in FIG. 10 a. In a heart-lung machine, withoutattached patient, the computer program 301 is executed by a computerunit, such as the control unit 302. The computer program is implementedon a computer-readable storage unit. During said filling and venting, afilling liquid from a filling liquid container located higher than thepatient module flows by gravity via a venous side of the system into areservoir and flows onwards into a blood pump located at the lower endof the reservoir. The computer program comprises code segments, whereinone code segment 310, first opens a controllable valve for a ventingline of a filter and, after a response from an upper filling levelsensor in the reservoir, is closed. The computer program 301 ispreferably suitable for carrying out the below-mentioned embodiment of a“first method.” A kit for a heart-lung machine comprises a patientmodule, a table set 33, and a filling liquid container 45 for a fillingliquid.

Another computer program 401 for controlling the filling and venting ofa patient module is shown in FIG. 10 b. In a heart-lung machine, withoutattached patient, the computer program is executed by a computer unit,such as the control unit 302. The computer program 401 is implemented ona computer readable storage unit. During said filling and venting, afilling liquid from a filling liquid container located higher than thepatient module flows by gravity via a venous side of the system into areservoir and flows onwards into a blood pump located at the lower endof the reservoir. The blood pump is located below a lower filling levelsensor of the reservoir. The computer program comprises code segments,wherein one code segment 410, upon detection of the filling liquid inthe reservoir by the lower filling level sensor, closes the fifthcontrollable valve 25 (HC5), as a result of which, a venous connectionbetween volume dose inlet and the reservoir is separated, and thefilling liquid flows only through the venous line via a bypass to anarterial filter, and, by means of the pressure applied, the filter isfilled in a retrograde manner from the outlet side by gravity. Thecomputer program 401 is preferably suitable for carrying out thebelow-mentioned embodiment of a “second method.”

FIG. 9 a shows a schematic diagram of the steps of a first method, andFIG. 10 a shows a schematic diagram of a computer program for carryingout the first method.

FIG. 5 shows the above-explained circulation system for the first method200, as shown in FIG. 9 a. This method 200 is a method for filling andventing a patient module in a heart-lung machine. A patient is notattached thereto during the filling procedure. The method comprises thestep 210, in which a filling liquid from filling liquid containerlocated higher than the patient module flows by gravity via a venousside of the system into a reservoir and flows onwards into a blood pumplocated at the lower end of the reservoir. The first controllable valve21 HC1 is opened for the venting line of the filter 5. In a further step212, the first controllable valve is closed after a response from anupper filling level sensor in the reservoir.

After the start of the venting procedure, all the process steps runautomatically until the venting procedure is completed. After the start,the HC3 23 opens the volume dose line. The filling liquid from thefilling liquid container 45 located higher than the patient module flowsby gravity via the venous side of the system into the reservoir 2 andflows onwards into the blood pump 6, in the form of a centrifugal pump,located at the lower end of the reservoir 2. The HC2 22, HC4 24 and theQAHC 20 and the roller pump 39 with hose clamp function are opened. TheHC1 21 for the venting line of the filter 5 is likewise opened, and itis closed only after the response of the upper filling level sensor 10in the reservoir. The roller pump 39 is likewise closed after theresponse of the upper filling level sensor 10 in the reservoir, and inthis way no more air can escape through the venting path 35 to thecollecting bag 36, and the filling of the reservoir 2 via the fillingliquid container 45 is stopped. Depending on the state of filling of thereservoir 2, the roller pump 39 is opened or closed. When the fillingliquid reaches the upper filling level sensor 10 in the reservoir 2, itis assumed that the downstream components are filled by gravity withfilling liquid. After the upper filling level sensor 10 has beenreached, the HC1 21 is closed in order to ensure the continued activefilling of the filter 5. An advantageous air cushion forms.

Because of the structure of centrifugal pumps, a liquid has to bepresent in the pump in order to permit the active delivery of liquids.There is no suction behaviour for air in the pump head, as in adiaphragm pump.

The blood pump 6 located in the patient module is oriented in itsinstallation position in such a way that it can be filled by gravitywith filling liquid through the upwardly directed tangential outlet 62and through the axial inlet 61 (see FIG. 3). The air rises in the bloodpump 6 and is led off via the outlet 62.

After gravitational filling has taken place, a start/stop movement ofthe pump 6 ensures that the air located in the blood pump is transportedto the outlet 62 and led off. During a stop of the pump, the air canrise in the direction of the pump outlet 62, and it can be transportedoff by starting the blood pump 6.

The arrangement of reservoir 2 and blood pump 6, namely below themaximum filling level of the reservoir 2, ensures that the blood pump 6is filled by gravity and, in this way, there is always liquid in theblood pump 6 during the venting procedure.

The blood pump 6 filled with filling liquid is operated at periodicintervals at a low speed, depending on design and delivery rate. Thefilling liquid is conveyed from the reservoir 45 into the oxygenator 3and onwards into the arterial filter 5. By means of the slow filling ofthe filter 5 from the inlet side 50, the filter is only partiallyfilled. The upper area of the filter membrane 52 remains unwetted by thefilling liquid and is therefore still air-permeable. Any air inclusionscan cross from the filtered side 54 to the unfiltered side 53 and be ledoff. The introduced filling liquid passes through the lower part of thefilter membrane to the filtered output side 54 and fills the downstreamcirculation system. The air from the hose attached to the filter outputside 54 can escape into the filter 5 and to the unfiltered side 53through the unwetted part of the filter membrane 52.

Moreover, an air cushion forms in the filter 5 on account of the closedventing line, since the HC1 is closed, and the filling liquid located atthe filter output. The air cushion advantageously damps the flowbehaviour of the incoming filling liquid.

After a defined filling time at a low speed and thus a low deliveryrate, the speed of the blood pump 6 is increased in steps to a constantvalue, and the bypass 40 is clamped by closure of the hose clamp HC4 24,and in this way the attached table set 33 has liquid passed through itand is vented.

In the following step, the HC4 24 is opened again and the speed of theblood pump 6 is further increased. By means of the further closure ofthe HC4 24 and a further increase of the speed and therefore an increasein the output rate of the blood pump 6, more liquid is passed throughthe table set 33 and the latter is further vented. During this, the HC121 is opened, i.e. the venting clamp of the arterial filter 5. The airremaining in the upper part of the filter can thus escape.

In order to vent the bypass again, the HC4 24 is opened again. If, inthe last steps, air in the system is detected by the air bubble sensor30, the QAHC clamps the table set 33 off, the HC4 24 opens, and the airin the system can be led off via the reservoir 2. By means of thefilling level sensors in the reservoir 2, the liquid level ispermanently monitored, so as to supply the system with sufficientfilling liquid.

The venting procedure is recorded and thus documented in readable form.The indexing positions of the hose clamps, filling states of thereservoir, switch-on and switch-off times, the response of the airbubble sensor and other parameters such as pressure and flow can bestored.

The venting procedure can also be carried out during transport or mobileuse of the heart-lung machine. FIG. 7 shows a schematic overview of acirculation system for the first method 200 with integrated pressuremeasurement. The circulation system is like the one for the previouslyexplained first method, but with four controllable valves, here hoseclamps. The clamps HC1 21 and HC2 22 shown in FIG. 6 are here combinedinto one hose clamp 21 a by integration of the pressure measurement intothe hose system between blood pump band oxygenator 3 and oxygenator 3and filter 5.

FIG. 6 is a schematic overview of a circulation system for a secondmethod 220 with retrograde filling. FIG. 9 b is a schematic diagram ofthe steps of the second method 220. FIG. 10 b is a schematic diagram ofa computer program 401 for carrying out a second method.

The conditions are as in the first method, only with the blood pump 6 onthe reservoir 2, which is located below the lower filling level sensor11 of the reservoir 2. The blood pump 6 can also be arranged below thelower edge of the reservoir 2. An additional controllable valve, herethe hose clamp HC5 25, is arranged in the venous line between volumedose inlet and reservoir 2 and a feed point of the filling liquid, whichfeed point is higher than the reservoir, the filter and the oxygenator.

The second method 220 is a method for filling and venting a patientmodule in a heart-lung machine, without attached patient. A fillingliquid from a filling liquid container located higher than the patientmodule flows by gravity via a venous side of the patient module into thereservoir 2 and flows onwards into the blood pump 6 located at the lowerend of the reservoir 2. The blood pump is located below the lowerfilling level sensor 11 of the reservoir 2.

When the filling liquid in the reservoir 2 is detected, the fifthcontrollable valve 25 (HC5) is closed by the lower filling level sensor11. Therefore, by means of the fifth controllable valve 25, a venousconnection between volume dose inlet and the reservoir 2 is separated.The filling liquid now flows only through the venous line via the bypass40 to the arterial filter 5. By means of the pressure applied bygravity, the filter is filled in a retrograde manner from the outletside 51 (see FIG. 2).

After the start of the venting procedure, all the sequences are carriedout automatically until the venting procedure is completed. After thestart, HC3 23 opens the volume dose line. The filling liquid from thefilling liquid container 45 located higher than the patient module flowsby gravity via the venous side of the system into the reservoir 2 andonwards into the blood pump 6, in the form of a centrifugal pump,located at the lower end of the reservoir. HC1 21, HC2 21, HC4 24, HC525 and the QAHC 20 and the roller pump 39 with hose clamp function areopened.

The filling liquid flows by gravity at the same time through the venousline into the reservoir 2 and via the bypass 40 in the direction of theoutput of the arterial filter 5. Because of its higher position ofinstallation, the filter 5 cannot be filled, since the filling liquidflows off into the reservoir 2.

The blood pump 6 located in the patient module is oriented in itsinstallation position in such a way that it can be filled by gravitywith filling liquid through the upwardly directed tangential outlet 62and through the axial inlet 61 (see FIG. 3). The air rises in the bloodpump 6 and is led off via the outlet 62. As soon as the filling liquidin the reservoir 2 has reached the lower filling level sensor 11 in thereservoir, the downstream blood pump is filled completely with fillingliquid.

The lower filling level sensor 11 detects the filling liquid in thereservoir, and HC5 25 is closed. The venous connection between volumedose inlet and the reservoir 2 is thus separated. The filling liquid canflow only through the venous line via the bypass 40 to the filter 5. Bymeans of the pressure applied by gravity, the filter 5 is filled in aretrograde manner from the outlet side. In this way, in the filter, theair can escape from the filtered side to the unfiltered inlet side (seeFIG. 2). The filling by gravity results in a gradual venting and fillingof the filter 5. The air can escape through the venting line on theupper part of the filter, and the filling liquid can flow onwards to theoxygenator 3. Retrograde filling likewise takes place in the oxygenator3. The air is led off through the venting line of the oxygenator.

In the next step, the HC5 25 is opened and the filling liquid flows intothe reservoir 2 again until the upper filling level sensor 10 detectsliquid. In this way, the blood pump 6 is activated and its speed isincreased in steps up to a constant value. Moreover, the bypass 40 isclamped by closure of the hose clamp HC4 24, and liquid flows throughthe attached table set 33.

In the following step, the HC4 24 is opened again and the speed of theblood pump 6 is further increased. By means of the further closure ofthe HC4 24 and a further increase of the speed and therefore an increasein the output rate of the blood pump 6, more liquid flows through thetable set 33 and the latter is further vented. The opened venting linesof the filter 5 and of the oxygenator, through HC1 21 and HC2 22, allowany air present in the components to escape to the reservoir 2.

By means of the closure of HC4 24 and QAHC 20, the venting lines of theoxygenator 3 and of the arterial filter 5 are again flushed in the laststep of the venting procedure.

If, in the last steps, air in the system is detected by the air bubblesensor 30, the QAHC 20 clamps the table set off, the HC4 24 opens, andthe air in the system can be led off via the reservoir 2.

By means of the filling level sensors in the reservoir 2, the liquidlevel is permanently monitored, so as to supply the system withsufficient filling liquid.

FIG. 8 is a schematic overview of a circulation system for the secondmethod with integrated pressure measurement.

The circulation system is structured as described in FIG. 6 for thesecond method 220, but with only five hose clamps. HC1 21 and HC2 22 arecombined into one hose clamp 21 a by integration of the pressuremeasurement into the hose system between blood pump band oxygenator 3and oxygenator 3 and filter 5. The blood pump 6 is arranged below thelower edge of the reservoir.

The venting procedure is recorded and thus documented in readable form.The indexing positions of the hose clamps, filling states of thereservoir, switch-on and switch-off times, the response of the airbubble sensor and other parameters such as pressure and flow can bestored.

The venting procedure can also be carried out during transport or mobileuse of the heart-lung machine.

After the filling and venting procedure, the patient is attached asfollows. The patient is made ready during the filling procedure, with anarterial needle being introduced into the femoral artery and with avenous needle being introduced into the femoral vein of the patient.After the system has been filled, the table set filled with the systemis separated (severed) at the middle and plugged without air inclusionsonto the prepared needles and perfusion commenced.

A number of medical procedures can then be carried out on the patient.Examples of medical applications are, among others, an emergency use inacute heart failure (cardiogenic shock); heart support in order to avoidorgan damage; lung failure (ARDS); high-risk interventions on the heart(PCI [stent], DAVI [heart valves]); support in beating-heart surgery(CABG [bypass operation on the eating heart]); perfusion of donorcandidates for organ transplantation; temperature stabilization ofhypothermic patients (warming the patient to body temperature);temperature control of the patient=>hypothermia, deliberate lowering ofthe body temperature, e.g. stroke.

An exemplary method of using the described heart-lung machine afterpriming is now outlined. First the heart-lung machine is primed, orfilled, with a priming fluid such as sterile saline—preferably in amanner as described above. Once initiated, the priming can take place inan automated manner without human intervention. The machine is thenswitched from the filling (or priming) mode into an automatedoperational mode. Once primed, the machine is fluidly coupled to thecirculatory system of the donor through a vein to the venous coupling ofthe machine and through an artery to the arterial coupling of themachine. The method may include the addition of drugs or other additivesto the blood by way of the heart-lung machine. For example, ananticoagulant may be added to the blood to prevent clotting. The organsto be donated may be sustained until transplantation using theheart-lung machine or they may be sustained by the heart-lung machine,harvested, and transported separately before transplantation. Theheart-lung machine may prevent decomposition of the organ(s) untilshortly before transplantation of the organ to an organ receiver. Theviability of one or more organs is maintained in the organ donor forsubsequent transplantation. When the organ is ready to be implanted tothe organ receiver, the donor body or harvested organ is disconnectedfrom the heart-lung-machine.

In addition, or alternatively, one or more harvested organs may be keptalive by means of the heart-lung machine after harvesting. The organsmay then be perfused during transport by the heart lung-machine. Organsin particular suitable for such transport after harvesting comprise, butare not limited to, the heart, lungs, liver, or limbs. However, this isunder certain circumstances not feasible for some organs, such as eyes.Under such circumstances certain organs, such as eyes, are preferablysustained and kept from decomposing, by perfusing the entire body of adeceased, brain dead, or clinically dead organ donor.

In this manner, the method allows for one or more organs to betransported from one location to another location for transplantation.Transport is in particular facilitated by using the heart-lung machinein accordance with the afore described embodiments. The organs may bekept in a condition that allows to prevent a decomposition of the organthat would occur without interaction of the heart-lung-machine with theorgan. Blood or a blood substitute liquid may be used in the method forperfusing the organ(s).

Another exemplary method of using the described heart-lung machine afterpriming is now outlined. The method priming, or filling, the heart-lungmachine with a priming fluid such as sterile saline—preferably asdescribed above. Once initiated, the priming can take place in anautomated manner without human intervention. The machine is thenswitched from the filling (or priming) mode into an automatedoperational mode. When primed and operational, the machine is fluidlycoupled to the circulatory system of the patient through a vein to thevenous coupling of the machine and through an artery to the arterialcoupling of the machine.

The heart of the patient may optionally be slowed or stopped, ifnecessary. The blood returned to the patient is enriched with oxygen. Insome cases the blood temperature may be controlled to a body temperaturebelow normal body temperature and above a temperature where organs maybe damaged. Such a temperature is in the range of may today be achievedby placing the patient, or only the heart, during surgery in an icebath. However, by controlling the blood temperature, and perhaps coolingthe blood before reentering it into the patient via the venous vesselconnection, is an elegant solution where the body temperature is muchbetter controllable.

The method may include the addition of drugs or other additives to theblood by way of the heart-lung machine. For example, an anticoagulantmay be added to the blood to prevent clotting. The valve replacement orvalve repair is then performed during the medical procedure. The cardiacvalve is either replaced by an artificial valve unit or the valve isrepaired.

Valve repair may include positioning of an annuloplasty implant, aleaflet clip, or other medical devices suitable for repairing adefective cardiac valve. In this manner for instance regurgitation maybe treated. Alternatively, or in addition, surgical methods may beperformed where e.g. portion of leaflets are removed to correct adefective closure of the valve.

Valve replacement or valve repair is preferably performed in a minimalinvasive way. Percutaneous access to the heart via introducers andcatheters in the circulatory system is a suitable medical procedure foraccessing the heart in the present context.

Valve replacement may comprise removal of a dysfunctional heart valve.Alternatively, or in addition, an artificial valve is positioned at thelocation of the dysfunctional valve needing replacement. If for instancea so called stent valve is used, the dysfunctional valve may not need tobe surgically removed before positioning the artificial replacementvalve.

The cardiac valves to be repaired or replaced are for instance themitral valve or the tricuspid valve. When the valve replacement orrepair is concluded, the medical procedure is about to be finished. Thetools used to access the heart are removed. The introducer is removedand the wound is closed. When desired, the patient's heart is startedagain, if necessary, the patient is disconnected from the heart-lungmachine, and the operation of the machine is terminated.

Another exemplary method of using the described heart-lung machine afterpriming is now outlined. The method according to the present inventioncomprises priming, or filling, the heart-lung machine with a primingfluid such as sterile saline—preferably as outlined above. Onceinitiated, the priming can take place in an automated manner withouthuman intervention. When primed and operational, the machine is fluidlycoupled to the circulatory system of the patient through a vein to thevenous coupling of the machine and through an artery to the arterialcoupling of the machine.

The heart of the patient may optionally be slowed or stopped, ifnecessary. The blood returned to the patient is enriched with oxygen. Insome cases the blood temperature may be controlled to a body temperaturebelow normal body temperature and above a temperature where organs maybe damaged. Such a temperature range may currently be achieved byplacing the patient, or only the heart, in an ice bath during surgery.Controlling the blood temperature, and perhaps cooling the blood beforereentering it into the patient via the venous vessel connection, is anelegant solution whereby the body temperature and/or the hearttemperature is much better controlled.

In the case of a coronary artery bypass graft a graft vessel, such as asegment of saphenous vein, an internal thoracic artery, or a radialartery is taken from the patient, a cannulae is sutured into the heart,and cardiopulmonary bypass using the heart-lung machine is initiated.The aorta is clamped and the heart is stopped and cooled to, forexample, 29′C. One end of the graft vessel is sutured a coronary arterybeyond a blockage to be bypassed. The heart is then restarted, the otherend of the graft vessel is sutured to the aorta while the heart isbeating, and the heart-lung machine is disconnected from the patient.

The method may include the addition of drugs or other additives to theblood by way of the heart-lung machine. For example, an anticoagulantmay be added to the blood to prevent clotting while the heart isstopped.

In the case of percutaneous angioplasty or stent placement, a balloon isinflated inside a coronary artery to widen the passage or to expand astent that will widen the artery and support the artery in a more openconfiguration to improve blood flow therethrough. The heart may be, butis usually not stopped for percutaneous angioplasty or stent placement,but the expansion of the balloon catheter inside the artery may causethe artery to rupture and necessitate emergency heart surgery. Theheart-lung machine may be used in the event of such a complication orother complications that require the heart to be stopped or slowed. Theheart-lung machine may be, but need not be, primed as a precautionbefore a possible complication.

A person skilled in the art will appreciate that changes andmodifications can be made to the described examples without departingfrom the scope of the attached claims.

List of reference signs 5 filter 51 outlet 52 filter element 53unfiltered side 54 filtered side 55 venting attachment 56 top face offilter 6 blood pump 61 axial inlet 62 tangential outlet 1, 1a patientmodule 10 upper filling level sensor 100 position of upper filling levelsensor 11 lower filling level sensor 110 position of lower filling levelsensor 12 input from venous line to reservoir 2 13 upper part ofreservoir 15 venous line 17 volume dose line 18 venting line foroxygenator 2 reservoir 3 oxygenator 20 quick-action hose clamp QAHC 21hose clamp 1HC 1 22 hose clamp 2HC 2 23 hose clamp 3 HC 3 24 hose clamp4 HC 4 25 hose clamp 5 HC 5 28 screen in reservoir 2 30 bubble sensor 31flow sensor 32a, b connectors 33 table set 34 pressure gauge 35 ventingline 36 collecting bag 37 pressure gauge 38 pressure gauge 39 rollerpump 40 bypass 42 arterial line 45 storage container 200 method 1 210,212 method steps 220 method 1 230, 232 method steps 300 storage medium301, 401 computer program 302 processor, control unit 310, 410 programsegments

1. Method for filling and venting a device for extracorporeal bloodtreatment, such as a patient module in a system, such as a heart-lungmachine, without attached patient, wherein a filling liquid from afilling liquid container located higher than the device flows by gravityvia a venous side of the device into a reservoir and flows onwards intoa blood pump located at the lower end of the reservoir, wherein a firstcontrollable valve (HC1) for a venting line of a filter is opened and,after the response of an upper filling level sensor in the reservoir, isclosed, wherein an upper level of the filter is positioned higher thanthe upper filling level sensor, and a start-stop motion of the bloodpump is performed, as a result of which a stepped flooding of the filteris made.
 2. Method according to claim 1, wherein the blood pump filledwith filling liquid is operated at periodic intervals at a first, lowspeed, which conveys filling liquid from the reservoir into anoxygenator and onwards into an arterial filter, wherein the first speedis chosen such that a slow filling of the filter from the inlet sidetakes place, and the filter is only partially filled, and an upper areaof the filter membrane remains unwetted by the filling liquid andtherefore remains airpermeable for the further filling and ventingprocedure.
 3. Method according to claim 1, wherein the firstcontrollable valve (HC1) is closed, after the response of the upperfilling level sensor, in order to control the further active filling ofthe filter, wherein, after gravitational filling has taken place, saidstart/stop movement of the blood pump ensures that the air located inthe blood pump is transported to the outlet and led off, wherein, duringa stop of the blood pump, air rises in the direction of the pump outletand is transported off by starting the blood pump.
 4. Method accordingto claim 3, wherein, by means of the closed first controllable valve(HC1) and the thus closed venting line and the filling liquid located atthe filter output, an air cushion is created in the filter which dampsthe flow behaviour of the incoming filling liquid.
 5. Method accordingto claim 1, wherein, as a function of the response of the upper fillinglevel sensor, and therefore in accordance with the filling state of thereservoir, a second pump, such as a roller pump, in a venting channelfrom the reservoir to a collecting container is opened or closed. 6.Method according to claim 5, wherein, after the response of the upperfilling level sensor in the reservoir, the second pump is switched off,and therefore no more air can escape through the venting channel to thecollecting container, and the filling of the reservoir via the fillingliquid container is stopped.
 7. Method according to claim 3, wherein, atthe response of the upper filling level sensor, the filling liquidreaches the level of the upper filling level sensor in the reservoir,and the downstream components are therefore filled with filling liquidby gravity.
 8. Method according to claim 3, wherein the blood pumplocated in the device is a centrifugal pump and has an upwardly directedtangential outlet, wherein, in the method, the blood pump is filled bygravity with the filling liquid through the upwardly directed tangentialoutlet and an axial inlet, wherein air in the blood pump rises and isled off via the tangential outlet.
 9. Method according to claim 8,wherein air inclusions cross from the filtered side to the unfilteredside and are led off.
 10. Method according to claim 8, wherein theintroduced filling liquid flows through the lower part of the filtermembrane to the filtered output side and fills the downstreamcirculation system.
 11. Method according to claim 7, wherein air from ahose attached to the filter output side escapes into the filter. 12.Method according to claim 8, wherein, after a defined first filling timeat the first speed and thus first delivery rate, the speed of the bloodpump is increased in steps to a constant second speed value, and abypass is closed by closure of a fourth controllable valve (HC4), and inthis way an attached table set has liquid passed through it and isvented.
 13. Method according to claim 12, wherein, after a definedsecond filling time, the fourth controllable valve (HC4) is opened againand the speed of the blood pump is increased further to a third speedvalue during a third filling time, and wherein the fourth controllablevalve (HC4) is thereafter closed again and the speed of the blood pumpis increased further to a fourth speed value, wherein the increase inthe delivery rate of the blood pump means that the table set has moreliquid passed though it and is further vented, wherein in the meantimean opening of the first controllable valve (HC1) takes place and the airremaining in the upper part of the filter thus escapes, and wherein thefourth controllable valve (HC4) is thereafter opened again in order tovent the bypass once more.
 14. Method according to claim 12, wherein airin the system is detected by means of an air bubble sensor and, upondetection of air bubbles, a controllable valve (quick-action hose clampQAHC) switches off the table set, the fourth controllable valve (HC4)opens again, and the air in the system is led off via the reservoir. 15.Method according to one of claims 1 to 14, wherein, by means of thefilling level sensors in the reservoir, the liquid level is permanentlymonitored, so as to supply the system with sufficient filling liquid.16. Method according to one of claims 1 to 15, wherein the ventingprocedure is recorded and thus documented in readable form, wherein, forexample, indexing positions of the controllable valves, filling levelsof the reservoir, switch-on and switch-off times, the response of theair bubble sensor and other parameters such as pressure and flow arestored.
 17. Method according to one of claims 1 to 16, wherein theventing procedure is carried out during transport, and/or wherein themethod is a method for fully automatic venting, and wherein, after thestart of the venting procedure, all the sequences are carried outautomatically until the venting procedure is completed.
 18. Methodaccording to claim 17, wherein, after the start, a third controllablevalve (HC3) opens a volume dose line (17) through which a filling liquidfrom a storage container (45) can be introduced into the circulation ofthe device, and wherein a second controllable valve (HC2, 22), a fourthcontrollable valve (HC4, 24) and a quick-action hose clamp (QAHC, 20)and also a roller pump (39) with hose clamp function are opened. 19-69.(canceled)